Tuesday 20 May 2008 06.13 EDT
First published on Tuesday 20 May 2008 06.13 EDT

Britain's largest power station, Drax, launched a £50m project yesterday aimed at replacing 10% of the coal it uses with biomass. Mixing materials such as wood chips, sunflower husks or grasses with coal to generate electricity could reduce the power station's annual carbon dioxide emissions by several million tonnes.

Executives from Drax, in North Yorkshire, signed a deal with Alstom to build a processing plant that could prepare 1.5m tonnes a year of biomass to fuel the power station's furnaces. Under the plans, biomass would be ground into a fine powder and injected directly into the coal-fired boilers. Building work for the plant will start this year and the first part of the facility is expected to be completed by the end of 2009.

Dorothy Thompson, chief executive of Drax, said the co-firing technology would save 2m tonnes of CO2 and help the power station towards its target of a 15% cut in carbon emissions by 2012. "Last year, we set ourselves the target of 10% of co-firing of biomass - that's equal to the output of about 500 wind turbines. In capacity terms, that's 400MW. That will make us the single biggest biomass-generating unit site in the world."

She added that, in recent years, co-firing coal with biomass fuels had emerged as a credible renewable technology. "We think of it as the forgotten renewables technology; we think it's very important and can deliver a significant amount of the carbon-abatement needed across the world."

Neil Crumpton, of Friends of the Earth, said using biomass in power stations or combined heat and power schemes was a better use of the resource than turning it into biofuels. "Co-firing with biomass is a reasonable way forward; it's a logical extension of what they're [Drax] already doing and I've got no qualms about it. If it helps build the sustainable biomass market in the UK, then all well and good."

Drax produces up to 7% of Britain's electricity and is one of the country's biggest emitters of greenhouse gases. To test whether co-firing would work, Drax has used a 2-3% mix of biomass in some of its coal-fired boilers for several months already. In their current experiments, the biomass fuel is mixed directly into the coal as it burns but this technique would not work for larger quantities of biomass.

"When you burn just a few percent of biomass, you can afford to use exactly the same lines as coal," said Patrick Fragman, managing director of Alstom, which will build the biomass processing plant at Drax. "But when you're going through the steps Drax is doing today, you need a dedicated infrastructure."

Peter Emery, production director at Drax, said the new plant was a crucial part of the power station's attempt to increase its biomass usage. He said it would be able to handle a wide variety of biomass fuels, which burn in different ways. Drax engineers estimate that it will take 1.5m tonnes of biomass a year to replace the energy that comes from 1m tonnes of coal.

If co-firing coal with biomass proves successful, Thompson said Drax may raise the proportion of plant material it adds to its fuel mix, perhaps to 20%.